There are numerous different designs of electrical cable glands on the market and which embody inner and outer seals, the outer seal being adapted to seal onto the outer sheath of an electrical cable, in use, and the inner seal being adapted to seal onto the inner sheath. An armor clamp assembly is provided between the two seals to clamp the armor wires of an armored electrical cable.
As indicated in our existing South African Pat. No. 84/8614 and United States counterpart thereto (the parent application in this case) such cable gland assemblies can have a weak point in their design in that, in most cases, an internally screw-threaded tubular member receives an externally screw-threaded member and moisture or vapors can travel along the screw-thread and thereby gain access to the interior of the electrical gland between the inner and outer seals thereof.
Our said earlier patent proposed the provision of a cylindrical sealing surface on the outside of one of such parts of a cable gland which was to be in sealing engagement with a peripheral skirt extending from the other of such parts to bridge the entrance to such screw-thread.
However, manufacturing tolerances on such an arrangement have proved to be difficult to maintain and, while such an arrangement operates effectively, it is the object of this invention to provide a simplified and more easily manufactured cable gland which provides an equivalent seal arrangement.
Furthermore, commercially available cable glands are not particularly well suited to use in corrosive surroundings such as in submersible pumps or other submerged locations in corrosive liquids or simply in corrosive environments such as coastal locations or chemical plants The only way in which contact with such corrosive liquids or environments is prevented is by a rubber or plastic shroud which generally has not proved to be satisfactorily effective. It is thus another object of this invention to provide a cable gland which has superior corrosion resistance when compared at least to most prior art cable glands.